Problem: If $a + b + c = -9$ and $x + y + z = -7$, what is $-10b - 6z - 10a - 10c - 6y - 6x$ ?
Explanation: $= -10a - 10b - 10c - 6x - 6y - 6z$ $= (-10) \cdot (a + b + c) + (-6) \cdot (x + y + z)$ $= (-10) \cdot (-9) + (-6) \cdot (-7)$ $= 90 + 42$ $= 132$